59 lines
1.1 KiB
Go
59 lines
1.1 KiB
Go
package builtin
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import (
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"encoding/json"
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"math"
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"git.xdrm.io/go/aicra/typecheck"
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)
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// Int checks if a value is an int
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type Int struct{}
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// NewInt returns a bare number type checker
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func NewInt() *Int {
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return &Int{}
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}
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// Checker returns the checker function
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func (Int) Checker(typeName string) typecheck.CheckerFunc {
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// nothing if type not handled
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if typeName != "int" {
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return nil
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}
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return func(value interface{}) bool {
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_, isInt := readInt(value)
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return isInt
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}
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}
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// readInt tries to read a serialized int and returns whether it succeeded.
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func readInt(value interface{}) (int, bool) {
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switch cast := value.(type) {
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case int:
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return cast, true
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case uint:
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overflows := cast > math.MaxInt64
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return int(cast), !overflows
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case float64:
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intVal := int(cast)
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overflows := cast < float64(math.MinInt64) || cast > float64(math.MaxInt64)
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return intVal, cast == float64(intVal) && !overflows
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// serialized string -> try to convert to float
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case string:
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num := json.Number(cast)
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intVal, err := num.Int64()
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return int(intVal), err == nil
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// unknown type
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default:
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return 0, false
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}
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}
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